Can't replicate results via ArcObjects seen when data is projected on the fly

I'm creating polygon's (saving to a feature class) from lat/long data into geographic GCS_WGS_1984. If I overlay those polygons in ArcMap into a data frame that is set to NAD_1927_StatePlane_Oregon_North_FIPS_3601 and select a transformation of NAD_1927_To_WGS_1984_6 the polygons draw where I expect them to.

If I try and make this same project and transformation in code (saving the results to a different feature class) and then add it to the map (that has the same projection ... NAD_1927_StatePlane_Oregon_North_FIPS_3601) the polygon seems to line up 400+ ft. to the west. Any thoughts as to what I'm doing wrong?

The target is NAD27, right? Try changing the transformation direction to Reverse rather than Forward in the ProjectEx command. The only other thing I can think to check is that the output geometry is tagged as NAD27.

The target is NAD27, right? Try changing the transformation direction to Reverse rather than Forward in the ProjectEx command. The only other thing I can think to check is that the output geometry is tagged as NAD27.

I think it was a combo of changing to reverse and also changing the way the polygon was created. Before the polygon was generated (in some cases) where the last point didn't match the first and no error was thrown (via IPointCollection::Add). By creating the polygon using the geometrybridge approach this issue was noticed and now polygon 'integrity'' seems better and methods such as projectex and buffer are behaving much better.